In general, a wrench is used for the rotative operation of a rotatively operated member having an operated portion as described above. In a case of a usual wrench, however, it is required that the wrench is once removed from the rotatively operated member every time the rotatively operated member is rotated over a certain angle and thereafter, the wrench be caught again on another engaging surface of the operated portion of the rotatively operated member. This operation is troublesome and especially, the wrench is not suitable for a long-time operation. Therefore, a special tool of a ratchet type is also used which is designed so that when a handle is turned in one direction, a rotatively operated member is rotated, but when the handle is turned in an opposite direction, a rotatively operating force is not transmitted to the rotatively operated member. However, such special tool can rotate the rotatively operated member only in one direction and for this reason, when the rotatively operated member is to be rotated in an opposite direction, it is necessary to recatch the tool with an opposite orientation each time. It is desired in many cases that the rotatively operated member, after being rotated in one direction, is rotated in an opposite direction. For example, in a case of a rotatively operated member such as a tie rod of an automobile, the adjustment of the length of the rotatively operated member is carried out by the rotation of the latter and hence, it is necessary to rotate the rotatively operated member in opposite directions for the fine adjustment. In such a case, the operation is rather complicated with the tool for rotating the rotatively operated member only in one direction as described above.
From such viewpoint, an improved wrench has been proposed (see Patent Document 1, for example), which is designed so that a rotatively operated member can be rotated in a desired direction by the reciprocally turning operation in a range of relatively small angles, while ensuring that a rotatively operating force in any direction can be applied to the rotatively operated member. In the improved wrench, a stationary jaw and a movable jaw are provided at a tip end of a handle grasped by an operator, so that when an operated portion of the rotatively operated member is located between the stationary jaw and the movable jaw and the handle is pushed to the operated portion, the movable jaw is turned to a position where the operated portion of the rotatively operated member is clamped between the movable jaw and the stationary jaw, and when the pushing force to the handle is weakened, the movable jaw is turned from the clamping position to an unclamping position.
[Patent Document 1]
Japanese Patent No.2913251
However, the wrench described in Patent Document 1 has a problem that a means is required for detecting a state in which the handle has been pushed to the operated portion of the rotatively operated member, inevitably resulting in an increase in number of parts, an increase in cost and moreover, an increase in weight.